I would say vibrations, but is there choices?
Answer:
See explanations below
Explanation:
According to Newtons second law of motion
F = mass * acceleration
F = ma
If mass of an object is decreased to half, then m₂ = 1/2 m
If acting force is reduced by quarter, then F₂ = 3/4 F
F₂ = m₂a₂
3/4F = 1/2m a₂
Divide both expressions
(3/4F)/F = (1/2m)a₂/ma
3/4 = 1/2a₂/a
3/4 = a₂/2a
4a₂ = 6a
2a₂ = 3a
a₂ = 3/2 a
Hence the acceleration of its motion will be one and a half of its original acceleration.
Answer:
The time interval is 
Explanation:
From the question we are told that
The length of the string is 
The mass of the string is 
The tension on the string is 
The velocity of the pulse is mathematically represented as

Where
is the linear density which is mathematically evaluated as

substituting values


Thus


The time taken is evaluated as

substituting values


Take your time, do not get distracted , do not talk and focus on the exam